Electronic data storage devices, e.g., hard disk drives or “HDDs,” perform essential commercial and personal functions in today's digital information-intensive world. As our reliance on these devices increases, so do the performance requirements of these devices, including their combined requirements for speed and reliability. Ongoing goals for new hard disk drive products are to increase data capacity and to reduce or minimize the occurrence of data storage errors.
Commercial hard disk drives are constructed of certain common components that include a structural base that defines an interior (e.g., a “cavity”), and a cover that encloses and seals the interior. The cover includes a rigid planar, e.g., flat, sheet often made of metal that is secured to the base and covers the interior. Within the interior are interior components at such as a stack of rotatable magnetic recording disks, reading and recording heads, motors, actuators, optional filters or environmental control modules, and electronic components that are adapted to communicate and transfer electronic data to and from an external electronic device.
Like other computer and electronic products, each next version or next generation of a hard disk drive product is expected to achieve an ever-increasing level of performance. Improved performance can mean a higher total amount of data storage capacity, increased speed and reliability, or all of these. To increase the data storage capacity of a hard disk drive, options include: placing more data onto each of multiple hard magnetic disks contained in a hard disk drive device (i.e., to increase “areal density” of the hard magnetic disks, which is a measure of the quantity of information bits that can be stored on a given area of disk surface); and placing more hard magnetic disks at the interior of a hard disk drive of a given exterior size, by increasing the interior space of the device.
One specific option for improving performance and storage density is to include a low-density atmosphere at the disk drive interior, for example an atmosphere of helium. A low density interior atmosphere can reduce the amount of drag force that affects a spinning disk or a stack of closely-spaced spinning disks. The reduced drag can significantly reduce the amount of power required to cause a disk stack to spin. Also, the low density atmosphere can reduce the amount of unwanted, non-rotational movement or “flutter” that occurs in a spinning disk, or undesired movement of a suspension assembly that works in conjunction with the spinning disk. Given that data is stored on data tracks on the spinning disks, reducing unwanted motion of a disk or suspension assembly can allow for reducing the width or pitch of the data tracks, which allows for increased track density, and consequently areal density.
A different general approach for achieving continued performance improvements is to increase the internal space of a disk drive by reducing the size of the components of the enclosure, such as the base or cover. Reducing a thickness dimension of a cover can increase the interior space of the hard disk drive. Even if by just a little, this increase in the amount of interior space may be useful to increase the storage capacity of a hard disk drive.